Inner charge container for fire extinguishers



April 10, 1962 c. K. HUTHSING, SR 3,028,918

INNER CHARGE CONTAINER FOR FIRE EXTINGUISHERS Filed Jan. 29, 1959 44 nyY 44 I a l INVENTOR.

United States Patent @fifice 3,928,918 Patented Apr. 10, 1962 3,tl28,918INNER CHARGE CONTAINER'FOR FKRE EXTlNGUISI-IERS Charles K. Huthsing, Sn,Culver City, Caiifi, a'ssignor to The General Fire Extinguisher Co. ofPennsylvania,

Philadelphia, Pa e corporation of Pennsylvania Filed Jan. 29', 1959,Ser. Ne. 789,873 1 Claim. (Cl. 169-32) The present invention pertains toan improved fire extinguisher construction and more particularly to animproved container of molded plastic construction especially suited foruse in a pressure generating type fire extinguisher for holding a liquidreagent therein.

One important object of the present invention is to provide an improvedfire extinguisher container of high- 1y corrosion resistant and longlasting yet inexpensive construction.

Other objects of the invention are: to provide an improved container foruse in a pressure generating type fire extinguisher, which is longwearing, and highly corrosion resistant, yet inexpensive to manufacture;to provide an improved elongated tubular container of moldedconstruction and method of making it, the container having an integrallymolded closure at one end and an in tegrally molded inturned flange atits other end; to provide an improved elongated tubular container ofmolded plastic construction comprising two end-to-end slightly taperedtubular portions sealingly spliced together by means of a molded adapterring, the container being relatively inexpensive to manufacture, andcorrosion resistant to any desired degree, depending upon the materialof which it is molded.

The foregoing and other objects and advantages of the present inventionwill become apparent in the following detailed description of apreferred embodiment thereof, taken in conjunction with the drawing,wherein:

FIGURE 1 is an exploded perspective view of a molded plastic innercontainer for use in a first extinguisher according to the presentinvention;

FIG. 2 is a cross-sectional view, partly in elevation showing thecontainer installed in an otherwise conventional pressure generatingtype fire extinguisher; and

FIG. 3 is a fragmentary cross-sectional view partly in elevation showingthe extinguisher illustrated in FIG. 2 in an inverted position.

The pressure generating type fire extinguisher shown in the drawingincludes a molded plastic inner container it} according to a preferredembodiment of the invention supported within an outer casing, orpressure vessel 12, which as shown is of entirely conventionalconstruction. Normally, the outer casing 12 is filled with a watersolution of soda, and a liquid reagent such as a solution of aluminumsulfite, capable of rapidly generating gas when mixed with the sodasolution, is placed within the inner container 10. The fire extinguisheris normally stored in an upright position, as shown in FIG. 2. In theevent of a fire, the extinguisher is usually inverted, whereupon thereagent within the inner container flows out of the inner container 10,and mixes and reacts with the soda solution in the outer casing 12,generating gas under relatively high pressure, which acts to drive thesoda solution and the spent reaction mixture out of the casing 12through the nipple 14 and the hose 16.

A fire extinguisher is ordinarily emergency equipment, and is kept onstand-by for long periods of time, during which it must retain itsability to generate pressure, so that when an emergency arises and theextinguisher is put to use, it will be effective for its purpose. it isimportant, therefore, that the inner container 14} be im pervious toliquids, and corrosion resistant, so that the reagent contained withinthe inner container 13 does not leak out duringstand-by, periods andbecome mixed with the soda solution in the outer casing 12, therebydissipat ing theability of the extinguisher to develop pressure when itis called into service. The inner container It therefore, must beleakproof and must be able to withstand the corrosive eifects of thesoda solution 12 and of the foam generating reagent stored within theinner container 10 for long periods of time without developing even somuch as a pinhole leak;

The inner container of fire extinguishers of this type have heretoforebeen made of sheet metal coated with a waterproofing and corrosionpreventive material. It has been relatively difficult to make such sheet:metal containers water-tight and sufficiently corrosion resistant toretain their water-tight characteristics over relatively long periods oftime. In the sheet metal construction, the container is made from a flatpiece of. sheet metal, and includes a longitudinal seam extending forits full length, which must be soldered or welded, and a separate bottommember, which also must be soldered in place. The seams and joiningsincrease the difiiculty of applying a uniform protective coating andthereby serve to promote corrosion and leakage, besides involving arelatively high manufacturing cost.

According to the present invention the inner container 11'! is formed ofnoncorrosive molded plastic or other suitable material, and includes anintegrally molded bottom closure 26, and an integrally molded inturnedtop flange 22 for supporting the stopple 24, which normally closes theupper end of the container 10. The container 10 is molded in fourpieces, and includes a bottom portion 26, an upper tubular portion 28, asplice ring 32, and an upper guide portion 30, all of which are cementedtogether to form a sturdy container. The guide portion 39 guides thestopple 24 when the fire extinguisher is inverted during operation andinsures proper return of the stopple to its seated position upon theflange 22 when the extinguisher is returned to its normal uprightposition.

The container 10 is relatively long and of narrow diameter, and becauseof its proportions, as well as its integrally molded bottom closure 20and inturned flange.

22 at its upper end, it is not practical to mold it in a single piece,as the molded one piece container could not be withdrawn from the mold.The bottom portion 26 and the upper portion 28 are, therefore, moldedsepa rately and are joined together with or without the adapter, orsplice ring 32, by pressing said parts together and by securing andsealing them by means of an appropriate cement (not separatelydesignated). The bottom portion 26 is tapered so that it is of slightlygreater diameter at the top than at the bottom, in order to facilitatewithdrawal of the molding mandrel, or core member during manufacture,and the upper portion 28is made slightly wider at its lower end than atits upper end for the same reason.

The mating ends of the two portions 26 and 28 are made of substantiallythe same diameter so that they form a smooth juncture at the middle ofthe container. The splice ring 32 is provided with an outwardlyprojecting flange 34 about midway along its length and of a height aboutequal to the thickness of the wall section of the two portions 26 and28. The flange 34 acts as a stop when the splice ring 32 is inserted ineither one of the portions 26 and 28, and insures that the splice ring Ibe made of lead or any other desired material. An exterior shoulder 36and an axially projecting flange 38 are formed at the top of the upperportion 28 for receiving the guide portion 38, the bottom ring 49 ofwhich fits tightly around and is cemented to the flange 38.

The guide portion 30 includes an outwardly extending flange 42 at itsupper end for supporting the inner container 10 within the fireextinguisher. The flange 42 rests upon an inwardly projecting flange 46of the collar 44, which reinforces the top of the outer casing 12. Theflange 46 has an inside diameter just greater than the greatest diameterof the container ltl, and thus permits the inner container 10 to bereadily inserted into and removed from the outer casing 12,. The flange42 at the top of the guide portion 30 engages and rests upon the collarflange 46 for supporting the inner container 10 within the fireextinguisher. The handwheel cap 52 fits upon the collar 44 and abuts thetop of the flange 42, thereby limiting upward movement of the container18 and securing it in position.

The side walls 48 of the guide portion 30 are apertured as at 59 toprovide ready discharge of the contents of the container 10 into theouter casing 12 when the fire extinguisher is inverted to the positionshown in FIG. 3. The side walls 48 of the guide portion serve to holdthe stopple 24 when the extinguisher is inverted, and to guide thestopple so that it will fall back properly upon the flange 22 when theextinguisher is restored to its normal upright position.

The inner container 10 may be molded of any desired rnoldable material,such as a synthetic resin, hard rubber or the like, having the desiredcorrosion resistance and strength properties. Polyethylene has beenfound to be suitable for most presently known fire extinguisher uses,since it is relatively inexpensive, is easily moldable, and issubstantially inert to most presently used chemicals, as well as havingexcellent physical properties, such as tensile strength and resilience.

What is claimed is:

An elongated tubular container of molded plastic construction for use ina pressure generating type fire extinguisher or the like as the innercharge container thereof comprising a tapered generally tubular bottomportion having an integrally molded bottom closure and an open top, saidbottom portion being wider at its top than at its bottom end, a taperedgenerally tubular upper portion having a relatively wide lower end and arelatively narrow upper end and an inwardly offset axially extendingflange near its upper end, the lower end of said upper portion being ofsubstantially the same diameter as the upper end of said bottom portion,a splicing ring fitted within both of said portions and sealed theretofor joining said portions together, and a separately formed stoppleguide secured to said axially extending flange and extending upwardlytherefrom, said guide being generally tubular in shape and having aperforate circumferential wall to permit lateral flow of fluidtherethrough, said guide also having an annular, radially outwardlyprojecting flange at its upper end for axially supporting said innercontainer within a conventional fire extinguisher casing.

References Cited in the file of this patent UNITED STATES PATENTS1,170,927 Moore Feb. 8, 1916 1,646,226 White Oct. 18, 1927 1,788,375Banfil Jan. 13, 1931 1,973,734 Thomas et al. Sept. 18, 1934 2,751,025Austin June 19, 1956 2,838,261 Amos et al. June 10, 1958 FOREIGN PATENTS34,569 Norway Apr. 3, 1922 535,840 Great Britain Apr. 23, 1941

